Knee joint for artificial limbs



July 3, 1951 F. c. LUCAS ET AL 2,559,446

KNEE JOINT FOR ARTIFICIAL LIMBs Filed Sept. '7, 1950 2 Sheets-Sheet 1 v Q Ii www 2325 ILEMHH" July 3, 1951 F. c. L UcAs ET AL KNEE JOINT FOR ARTIFICIAL LIMBS 2 Sheets-Sheet 2 Filed Sept. 7, 1950 3mm/WMS'. l'z'ed' flacas 90a Fay .E Lucas:

atented july 3, i i r KNEE JOINT FOR ARTIFICIAL LIMBS v Fred C. Lucas and Roy P. Lucas,

Los Angeles, Calif.

Application September 7, 1950, Serial No. 183,642 8 claims. (el. 3 2) This invention relates to the knee joint of articial limbs and has as its primary object the provision of an articulate joint between the shank and thigh portions of an artificial leg which is so constructed as to provide security against buckling, which will offer resistance to rearward relative movement of the shank and thigh portions and permit greater freedom of forward movement thereof, and which may be readily regulated to conform to the natural step of the individual wearer.

Another object is to provide a knee joint for artificial legs which will afford differential friction controlled opposed swinging movements of the shank and thigh portions of the leg relative to each other, whereby flexing of the joint in swinging the shank portion rearwardly relative to the thigh portion, as in 'bending the knee, will be under greater frictional resistance than when the joint is flexed in swinging the shank portion forwardly relative to the thigh portion.

Another object is to provide a simple and readily operable means for independently varying the frictional resistance to articulation of the joint in either direction so as to enable adjustment of the joint to meet the requirementsI of various persons and also to meet varying needs of the wearer.

Another object is to provide a knee joint of the above character embodying a pivotal or hinged connection between the relatively swinging parts thereof which is resiliently supported to cushion impacts imposed thereon as when the artificial leg is employed in walking or running.

Another object is to provide an effective means for limiting articulation of the joint in one direction with a cushioning action.

Another object is to provide a joint which is noiseless and which requires no lubrication.

Another object is to provide a knee joint having relatively moveable parts including a pivot shaft hingedly connecting the parts and equipped with an over-running clutch cooperable with a friction element to permit comparatively easy relative swinging movement of the parts in one direction and afford a restrained relative swinging movement in the opposite direction, with means for varying such restrained movements and which also embodiesI a separate adjustable brake directly engageable with the shaft for applying varying resistance to relative movement of the parts independent of ,said friction element and the over-running clutch.

Another object is to provide a joint of the above character which is applicable to either the single or double type of knee joints; the former embodying a single hinged connection between the shank and thigh portions of an artificial leg while the latter embodies two pivots on a knee element one of which connects with the shank portion and the other of which connects with the thigh portion.

A further object is to provide a knee joint having the features of invention above stated in which the parts are so formed and arranged as to facilitate their assemblage and adjustment and which are durable for a long period of operation, yet which may be readily removed and replaced and parts easily renewed when excessively worn without the necessity of employing skilled artisans as is the case with some types of artificial limbs now on the market, the construction of the present knee joint being such that the user may ordinarily take it apart and reassemble it, make repairs if necessary and also make the desired adjustments to suit his needs.

With the foregoing objects in view, together with such other objects and advantages as may subsequently appear, the invention resides in the parts and in the combination, construction and arrangement of parts hereinafter described and claimed, and illustrated by way of example in the accompanying drawings, in which:

Fig. 1 is a view of an articial limb as seen in side elevation as equipped with a singleV pivot articulate joint constructed in accordance with the invention.

Fig. 2 is a rear elevational view of the joint with parts shown in section as seen in the direction of the arrow 2 in Fig. 1. l

Fig. 3 is a sectional View taken on the line 3-3 of Fig. 2 as seen in the direction indicated by the arrows, showing parts in elevation, and indicating in dotted lines an articulated position of the joint.

Fig. 4 is a plan View of the joint in the position shown in full lines in Fig. 3.

Fig. 5 is a view in section and elevation taken on the line 5 5 of Fig. 3 as seen in the direction indicated by the arrows Fig. 6 is an enlarged detail in cross section and elevation on the line 6 6 of Fig. 5 showing the mounting of the pivot shaft.

Fig. '7 is an enlarged cross sectional view as seen on the line 1-1' of Fig. 5 showing theoverrunning clutch and its associated brake element;

Fig. 8 is a view in side elevation of an artificial movably engaged with opposite side thereof, and indicating in dotted lines an articulated position of the joint.

Referring to the drawings morespeciiicially-A indicates generally the articulate knee joint embodying the invention and B and @designatesrespectively the thigh and shank portions of an artificial leg to which the knee joint A is ap.- plied. In the construction shown in Figs. l to 7 inclusive, the joint A embodies a hollow semispherical knee cap member I4 and a shell like semi-cylindrical socket member I5.l which members are hingedly connected. together for relative articulate movement with the lower part ofthe semi-spherical knee member I4-,telescoped in the upper portion of the socket member I5 in slightly spaced relation thereto. The upper portion ofV the knee member I4 is formed with a flange I5l which extends into the lower end of the thigh portion B and is firmly andrigidly secured thereto in any suitable fashion. The lower portion of the socketmember I5 is formed with a continuous marginal flange Il which extends into theupper end of the shank portion C and is firmly and. rigidlysecured thereto in any suitable fashion. The knee cap member I4 and the socket member I5 are formed of castmetal of a char-y acter which is light in Weight andA ofv requisite strength whereby the structure is renderedhighlyY durable.

The connection between the knee: and socket members I4 and I5 embodies a cylindrical hardened metal shaft` I 8. xed at its ends to the socket member I5 and revolubly and resiliently connected-to the knee member I4 and mounted to extend transversely of the latter rearward ofv the. center thereof but axially of the semi-,cylindricalVv portions ofthe knee and socket members the shaft I8 being revolubly supported atA eachy end thereof on roller bearings, Ill-I9. encompassedby resilient sleeves 21)?20 firmly affixedAV to and conformingr to diametrically opposed open ended cylinders 2I-.2I integrally formed on the side walls of the knee member I4.

The roller bearings I9 each embody a Imetallic cylindrical sleeve a' on the inner periphery of which is arranged a seriesV of spaced longitudinally extending needleY bearings bv as particularlyshownrin Fig. 6. The-outer ends of the shaft I8, bearings I9, and resilient sleeve terminate substantially co-planarwith the outer faces of` the side portions of the knee member I4 so that ar pair of parallel opposed lugs 22-22 formed on the upper rearwardmarginal portion ofthe socket member I5 may be positioned astride theknee. member I4; in sliding contact withV the opposite sides, thereof in assembling, the knee jointso as to position the lugs 22 to overlieand bearagainst the outer ends of the shaft I8.

Formed in the lugs 22; are circular openings 23 arranged to register withv internallythreaided recesses 24 formedin and extending axially ofthe ends of the shaftgl, and projectingthrough; the opening 2.3 are screws :25 -whharetehtlv.vetrethe threaded recesses-2,4.;-

sor wsY havingg ularheads 26g whiclfif are 4 counter-sunk in the outer faces of the lugs 22 and which heads are formed on their outer faces with lat sided recesses 21 for the reception of flat faced tools whereby the screws may be rotated in or out of engagement with the threaded recesses 24. The screws 25 serve to clamp the ends of the shaft I8 in tight not rotatable engagement with the socket member I5.

The mounting of the knee member I4 on the' shaft I8 and the connection of the ends of the shaft with the socket member I5 constitutes the pivotal connection between the knee and socket members, and. affords a ready means of assemblage of the articulate members of the knee joint. This construction also permits of the knee and socket member being readily separated, since by.y merely removing.) the screws 25 the yoke formed by the lugs 22 may be readily withdrawn outof engagement with the knee member I4 and whereby the shank portipn C of the artificial leg may be readily removed from. the knee joint to give access to the internal part, o f the `j oint for repairsv if need be.VV

'lihe shaft I'8is formed with spaced circumferential channels at the inner ends of the bearing sleeves; a in whichv are mounted split rings e which serve in abutting the inner ends of the sleeves-a to hold the shaft, I8 against longitudinal movement relative-tov they roller bearings I 9.

Encompassing the shaft I8 between the split rings e-e is a pair of friction brakes D. and E, which embody relativelyad-justable and separable arcuate metallic brake-shoes 28,-29fand 3&3- 3-I- respectively, eachl of,v which. shoes kis fitted. with; a, brake lining; fformed; of leather, rubberized. fabric or other suitablebrake, lining material.

The-brake members. D, and E extend parallel to. each. other in close spacedrelation and have their shoemembers 29 and 3 I connected together at one of theirends;by..a.plate portion 32y which` projectstangentiahy of the shaft Iand isrpivotally secured. bya.pivot.screwv 32.' to alug 32 formed on the innerface, of the semi-cylindrical. wall ofI the knee-.cap member I4. Thismounting of` the. brake members D/and E permits of slight lateralv oscillatory; yieldingA displacement thereof. underside thrusts; imposed. thereon occasioned` by yielding of the resilient sleeves 20 under vary-r ing relative. loadsv Qn s ide.ways.;strains imposed thereon during. use Qf the. legL structure. The

Y plate portion V32..normally. oyerlies a lug 33 on a spiderA 34 formed? on the lower end ofthe socket member I5. A cushion, 35.0n; the under side of. theplate 3-2 held5 invplace by the screw 32 is provided to abut the lug 33 which arrangement serves asal cushioned stop]x tolimit articulate movement` of. the knee.. joint in one direction as will be later describ e d The, brake :shoes: 28.. and. 29 ,of the brake D,A are connected together by., removable and adjustable screws, 3,6, and. 3] arranged on opposite. sidel of the-shaft. I8. with thebrake lining fthereof encircling.A and frictionally. engaging the latter; the frictionalengagement, of thefbrake DA With the shaft I 8:. .being Variedby. tightening or loosening the screws36-3L The brake shoes. 3,0and 3|. of the. brakeE are connectedl together by. removable and adjustable screws. 38; and. 33 .and have their. brake linings f. frictionally engaged withzthe -drum of an overrunning IVclutchl interposedbetween the brake E',` andthe shaftY IIL The over-running clutchF embadies the; conventional arrangement of a series of spaced rollersg. g; arranged between in,- elined faces otn teeth-.1. formed .enz-.the shaftf'l and extending longitudinally thereof; the rollers g being operable to effect wedge engagement between the inner periphery of the drum -40 and the inclined faces of the teeth h on rotation of the drum in one direction to eifect interlocking engagement between the drum 40 and the shaft I8 in said one direction and being operable on rotation of the drum in the opposite direction to shift the rollers out of engagement with the inclined faces of the teeth and thereby permit free rotation of the drum relative to the shaft. In this instance the incline of the teeth is such as to inhibit rotation of the shaft relative to the drum, or in other words, effect interlocking connection between the shaft and drum, whenthe socket member I5 is moved to swing the shank member C rearward relative to the knee member I4, or on rearward movement of the thigh portion B and the knee member I4 in a rearward direction relative to the socket member I I, or shank portion C as indicated in dotted lines in Fig. 1. y

The rollers g are held in place against longitudinal movement between the teeth h. by washers z'and y' encompassing the shaft I8 and loosely bearing against or slightly spaced from the opposite ends of the brake drum 40; the washer i abutting one of the split rings e while the washer y' is held in place by a split ring k engaging a cir cumferential groove in the shaft I8. 1 l By the provision of the over-running clutch F, rearward swinging of the thigh and shank portions B and C relative to each other is restrained by the action of the brake E, since the shaft I8 and the brake drum 4U are then automatically interlocked by the action of the over-running clutch. The extent of this restrained relative movement of the thigh and shank portions B and C is regulated by adjusting the screws 38 and 39,50 that the lining f of brake shoes 30 and 3'I will more tightly or more loosely frictionally engage the drum 40. The forward swinging movement of the shank portion C or socket member I'I is not effected by the over-running clutch F since the latter will then be free, but lwill be restrained to some extent according to the adjustment of the brake D; it ordinarily being desirable that this forward swinging movement be less retarded and more free than the opposite swinging movement.

Figs. 8, 9, and 11 illustrate the invention as applied to the knee joint of an artificial leg in which the joint embodies a pair ,of parallel vertically spaced but contiguous pivotal connections G and H; the pivotal connection G affording a hinge joint between the knee cap member A and the thigh portion Band the pivotal connection H aifording a separate hinge connection between the knee cap member A and the shank portion C. The pivotal connections G and H each comprise an assemblage of elements corresponding to the single pivot or articulate joint construction above described and set forth in Figs. 1 to 7 inclusive 'and vaccordingly the description of the partsof the hinge connection is applicable to the double pivot construction shown in Figs. 8 to 11 inclusive and therefor needs no repetition here. However, in order to produce the double pivot knee joint structure the knee cap member A is formed with upper and lower hollow semi-spherical end portions 4I and 42 engaged in socket members 43 and 44 rigidly connected to the thigh and shank sections B and C of the artificial leg in a usual manner, and in this instance the limiting of the relative swinging movement in one direction of the thigh and shank sections, or the socket membersv 43 and 44, to the knee cap members 4I and 42, is effected by forming the socket members-43 and 44 with back walls 45 and 46 respectively in over-'lapping relation to back walls 41 and 48 provided on the knee cap members 4I and 42, and fitting the latter back walls with silencing blocks 49-50 arranged to abut the walls 45-46 on forward movement of the thigh and shank members from their retracted positions and thereby limit such forward movement.

` Each of the shafts I8 in this double pivot arrangement is equipped with the pair of brakes E and E with over-running clutches F associated with the brakes E in the manner previously described in connection with the single pivot construction, and in this instance the pairs of brakes D E are independently fastened to the knee cap members 4I-42 by extending their connecting plates 32 into overlapped relation to lugs 5I and 52 formed interiorly oi' the knee cap members 4I and 42, and pivotally connecting the plates 32 to such lugs by pivot screws 53 and 54 ina fashion to permit slight lateral oscillatory movement of the brake assemblages.

In the operation of the invention the brakes D and E are adjusted by their respective regulating screws 38-31 and 38--39-to afford the requisite frictional resistance to articulate movementof the joint A according to the requirement of the individual wearer of the artificial leg; the brakes being adjusted so as to permit relatively free yet frictionally restrained forward turning movement of the knee cap member I4 on the shaft I8, at which time the over-running clutch F runs free, and to offer greater resistance to rearward turning movement of the joint through the medium of the brake E acting on the drum 40, which is then immobolized relative to the shaft I8 by the brake action of the rollers g and the inclined faces h of the over-running clutch. When the weight of the wearer is imposed on the artificial leg the frictional engagement of the brakes D and E is augmented by reason of the upward thrust of the shaft I3 from the shank C and the socket member I'I and the opposed downward thrust imposed on shoes of the brakes D and E through the knee cap member I4 and its connece tion to the brake shoes 29 and 3l afforded by the pivotal connection of the plate 32 with the knee cap member. The resilient sleeves 20 cooperate in this action in that they permit slight relative longitudinal movement of the knee joint members I4 and I5 and which relative movement is permitted by the provision of adequate clearance between the knee cap member I4 and its encompassing socket member I5.

The cushion sleeves 20 permit slight longitudinal tilting movement of the shaft IS under sideways strains, which movement is permitted without imposing excessive strains on the supporting connection between the brakes D and'E and the knee cap member I4 by reason of such connection comprising a Divot afforded by the screw 25.

As the knee joint swings under rearward movement of the thigh and shank portions B and C, as from the position shown in full lines in Fig. 1 to the position indicated in dotted lines, and as also indicated by the dotted lines in Fig. 3 relativeto the full lines, the plate 32 which normally abuts the lug 33 through the cushion 35 when the thigh and shank connections B and C are in their forwardmost position, then moves away fromvthe lug 33 with the knee cap member I4 ,and which movement under the frictional resistaccanita ance afforded by the brake: E maybe continued until the shank Vportion C swings backwardly against the thigh portion B, and thereafter, on forward movement of. the parts'under the resistance afforded-'by the brake D such movement will be limited by the plateV 32 abutting the lug 33 through the cushion 35.

The foregoing described operation applies particularly to the invention as applied to a single pivot knee joint,as shown in Figs. 1 to 8 inclusive, but also applies to the invention as. applied to the double pivot knee joint shown in Figs. 9 to 11 inclusive as far as the braking action on the pivot shafts I8 is concerned, which consti.- tutes the essence of the invention, but in the double pivot arrangement as here shown the rearward swinging movement of the joint is limited atV each end of the joint in the manner previously described.

It is to be noted that in the operation of the joint A, the brake D regulates the forward swing of the shank portion C so that it will not move too fast, while the brake E when properly adjusted controls the buckling action of the joint and stabilizes the bending of the joint under the loads imposed thereon.

While we have shown and described a specific embodiment of ourinvention, we do not limit ourselves to the exact details of construction set forth, andthe invention embraces such changes, modifications and equivalents of the parts and their formation and arrangement as come within the purview of the appended claims.

We claim:

1. In a knee joint for artificial limbs, a knee cap member having a. hollow semi-cylindrical portion, a socket' member encompassing a part of said semi-cylindrical portion, a shaft supported at its ends by said socket member, roller bearingsv on said shaft attached to said knee cap member and affording an articulate joint between said knee cap and socket members, an overrunning clutch on said shaft, within said knee cap member, a drum embodied in said clutch. a friction brake encompassing said drum, a friction brake encompassing Said shaft, and connections between said brakes and said knee cap member.

2. The structure called for in claim l together with adjustable means for independently regulating said brakes.

3. In a knee joint for artificial limbs, a knee cap member having a hollow semi-cylindrical portion, .a socket member encompassing a part of said semi-cylindrical portion in spaced relation thereto, a shaft rigidly supported at its ends by said socket member and extending axially of the semi-cylindrical portion of said knee cap member, roller bearings on said knee cap adjacent each end thereof, Va resilient sleeve encompassing each of said bearings attached to said knee cap member wherein said shaft and said knee cap member may oscillate relative to each other longitudinally of said shaft, an over-running clutch oncsaid shaft within said knee cap member, a drum embodied in said clutch, a friction brake encompassing said drum, a friction brake encompassing said shaft, and a pivotal connection between saidk brakes and said knee cap member.

4. In a knee joint for artificial limbs, a socket member having opposed upwardly extending lugs, a shaft extending between said lug, means detachably connecting said lugs and shaft holding the latter againstV movement relative' to said socket member, resilient' sleeves encompassing 8i saidshaft adjacent said lugs, roller Vbearings in;-V ter-posed betweeny said sleeves and, said sha-ft, a. hollow knee capy member having opposed cylin-l drical portions encompassing and engaging said resilient s1ee`vesv,-aipair of frictionbrakes attached to said kneey cap member encompassingv said; shaft, one of said brakes having direct frictional engagement with said shaft, an over-running clutch interposed betweenV the other ofY said brakes and said shaft, and a drum embodied in said Yclutch frictionally engaged by said last4 named brake, said clutch interlocking said shaft'v and drum on rear-ward articulation of the joint and freeing such shaftanddrum relative to each other on forward articulation of the joint.

5'. In aknee joint for artificial limbs, a socket member, a shaft, rigidly supported at its ends on said socket member, a knee cap member pivotally supported on said shaft, means for limiting relativer pivotal movement of said socket member andknee cap member in one direction, a brake frictionally engaging said shaft and connected to said knee cap member, a brake drum loosely encompassingl said shaft, means for interlocking said brake drumand shaft for collective rotationY in one direction only, and a second friction brake encompassing andeng-aging said drum connected tosaid knee cap member.

6. The structure called for in claim 5 togetherv with means for independently adjusting said brakes to regulate their respective frictional en. gagement with said shaft to said drum whereby 'said brakes may be set to oder greater resistance to articulation of the joint in one direction than in the other.

7. In a knee joint for artificial limbs, a knee cap member, a pair of opposed roller bearings carried by said knee cap member, a shaft supported in said bearings having flat outer ends terminating contiguous outer faces of said knee cap member and formed with axially extending internally threaded recesses, a socket member having parallel opposed lugs positionable astride said knee cap member in abutting relation thereto and-to the ends of said shaft, means for rigidly securing the ends of said shaft to said lug, a pair of friction brakes carried by said knee cap member interiorly thereof encompassing said shaft intermediate said bearings, a friction shoe on one of said brakes directly engaging said shaft, an over-running clutch on said shaft, a drum embodied in said clutch, and ya friction shoe on the other of said brakes frictionally engaging said drum.

8. The structure called for in claim 7 together with means for independently regulating said brakes relative to each other.

FRED C. LUCAS. ROY P. LUCAS.

REFERENCES CITED The following references are of record in the file of this patent: 'l

UNITED STATES PATENTS Number Name Date 2,279,962 Woodall Apr. 14, 1942 2,513,134 Borghausen June 27, 1950 2,542,567 Peters Feb. 20, 1951 FOREIGN PATENTS Number Y Country Date 495,281- Great Britain Nov. l0, 1938 

